The present invention relates to a method for fabricating a curved disc-shaped magnet coil, especially for particle accelerators, the conductors of which are wound around a coil form which has a convex outside and a concave inside and therefore, with a partially negative curvature, using elements pressing the conductor onto the inside of the coil form and the conductor turns already placed there, and which are secured in position after the winding process. The invention further relates to an apparatus for carrying out this method.
A similar superconducting magnet coil is known, for instance, from the literature reference "Fuji Electric Review", vol. 19, no. 3, 1973, pages 112-118. This coil, wound with superconductors, is curved along a length of circular arc with predetermined radius and predetermined arc angle, so that it has a convex outside and a concave inside. This magnet coil, the conductors of which are fixed in their geometric position by struts between these sides, is to serve as a lifting magnet for the contactless suspension guidance of a vehicle along a track.
Also in particle accelerators, storage rings for charged particles such as electrons must have corresponding curved dipole magnets due to their curved particle tracks. These magnets can be formed particularly in the shape of semicircles (see, for instance, "IEEE Transactions on Nuclear Science", vol. NS-30, no. 4, August 1983, pages 2531 to 2533) Because of the required high field intensities, superconducting windings are preferred for this purpose. In order to guarantee an unchanged position of the turns of these windings to be fabricated from corresponding conductors, these turns must first be wound around a suitably shaped coil form and fastened to the same. In this connection, however, the problem arises of winding with a negative radius of curvature in the region of the concave insides of the coil forms.
Magnets, the windings of which have negative curvature, can be fabricated, for instance, by laying the at least one conductor in slots without tension, and subsequent wedging. Also known is the successive clamping of the conductor, using special pressure elements such as individual clamps which can be attached to the outer edge of the coil form in stationary relationship. The conductor segments clamped by these elements must then be fixed piece by piece to the coil form and if applicable, to conductor turns already placed there, for instance, by cementing. Such winding techniques, however, are very complicated and time-consuming, especially for superconducting dipole magnets of storage rings.